What is usability testing for medical devices?
Usability testing is a structured process of evaluating medical devices and IVDs to verify their safety, intuitiveness, and user performance in real-life scenarios. According to MDR 2017/745 and IVDR 2017/746, such testing is mandatory when the user’s actions can directly impact the clinical outcome. The process follows IEC 62366-1 and is closely tied to risk management under ISO 14971.
Usability testing includes:
- formative evaluations – during product development,
- summative evaluations – final validation of the finished device,
- comparative testing – especially for updates to legacy devices.
Which devices require usability testing?
Usability testing is particularly important for high-risk devices (Class IIb and III), software-based devices (SaMD), and products used in critical care or home environments. It is also required when user interaction may directly influence clinical outcomes or patient safety.
Usability engineering in device design
Usability engineering is a user-centered design process that ensures a device can be used safely and effectively. It must be documented as part of the quality management system compliant with ISO 13485 and included in the technical documentation. The manufacturer must design user-device interaction in a way that minimizes use-related risks.
The process involves:
- identifying users and their needs,
- designing the user interface and instructions,
- analyzing use-related hazards and errors,
- conducting both formative and summative testing.
Usability engineering deliverables
Manufacturers must provide a complete usability engineering file as part of technical documentation.
- Usability engineering plan
- Use specification
- Hazard analysis (use-related)
- Formative evaluation reports
- Summative usability validation report
User and use environment analysis
Manufacturers must define intended users (e.g. clinicians, technicians, patients) and use environments (e.g. hospital, home, lab). This analysis includes cognitive, physical, and organizational limitations, as well as environmental factors that may affect device use.
Its outcome supports the development of training materials and instructions tailored to user capabilities.
User interface and instructions for use
The user interface includes all physical, digital, and informational elements through which users interact with the device. These elements must be ergonomic, unambiguous, and aligned with device functionality.
The instructions for use (IFU) form part of the technical documentation and must include:
- functional description,
- step-by-step usage instructions,
- warnings and contraindications,
- diagrams, technical data, service and certification details.
Usability testing and product development
Usability testing is carried out with representative users in simulated or real use conditions. It helps identify:
- operational difficulties,
- use-related errors,
- non-intuitive interface elements.
Results inform design and documentation improvements. Summative testing is required for Class IIb, III, and innovative devices.
Example of usability testing in practice
For example, in an infusion pump study, usability testing may involve programming dosage, responding to alarms, and handling emergency situations. Observed use errors must be documented, analyzed, and directly linked to risk management processes.
Common usability failures in medical devices
In practice, usability issues often arise from:
- overly complex interfaces
- unclear alarm systems
- mismatch between user expectations and device logic
- insufficient validation of real-use scenarios
Risk assessment in the usability context
Usability-related risks are considered clinical risks. As per ISO 14971, the manufacturer must identify potential use errors caused by:
- ambiguous signals or alarms,
- complex operational sequences,
- unclear or overloaded instructions,
- mismatch between user expectations and device behavior.
These risks must be mitigated through engineering or instructional controls and monitored via post-market surveillance.
What do notified bodies expect from usability testing?
Notified bodies expect clear traceability between identified use-related risks, defined test scenarios, and implemented risk control measures. Lack of consistency between these elements is one of the most common reasons for additional review cycles.
Common usability findings during audits
During audits, typical issues include missing validation reports, insufficient documentation of user interaction, and weak linkage between usability testing and risk management.
Link between usability testing and clinical evaluation
Usability data must support the clinical evaluation report (CER), particularly where user interaction can influence clinical outcomes or patient safety.
Usability of software as a medical device (SaMD)
For SaMD, usability focuses on:
- clarity of the graphical interface,
- accuracy of system messaging,
- reducing risk of misinterpretation,
- performance in various hardware environments and under stress conditions.
Software must include a user support system and instructional materials validated with end users.
Stability of active medical devices
Stability refers to the device’s ability to maintain performance over time and under environmental stress. Evaluation includes:
- resistance to temperature, humidity, vibration, and impact,
- performance during power loss or fluctuation,
- durability of mechanical and electronic components.
Stability data must be included in the technical file and reviewed by the Notified Body during conformity assessment.
Upgrading legacy devices under MDD
Legacy devices (previously certified under MDD) must be updated to meet MDR usability requirements. This includes:
- modernizing user interfaces,
- revising instructions for use,
- conducting new summative testing,
- reclassifying use-related risks after functional changes.
Such upgrades are essential for maintaining market presence after the MDR transitional period (until 2028), as per Article 120.
MDR requirements for usability
Annex I of MDR 2017/745 requires that devices be designed to:
- minimize use-related errors,
- ensure intuitive and unambiguous operation,
- enable correct use by intended users in the intended environment.
The final phase of usability evaluation is summative testing, which must be documented in a usability report. This report is part of the conformity assessment and is required for market approval.
Regulatory mapping of usability requirements
Usability engineering must be mapped directly to MDR Annex I requirements, ISO 14971 risk management, and IEC 62366-1 processes.
- Annex I – safety & usability requirements.
- ISO 14971 – identification of use-related hazards.
- IEC 62366-1 – usability engineering process.
Expert insight – usability in practice
In practice, the biggest challenge is not conducting usability testing itself, but designing realistic scenarios that reflect actual clinical workflows and user behavior.
How Pure Clinical can support your usability testing
Pure Clinical provides comprehensive support to medical and IVD device manufacturers in planning and executing usability testing. Our services include:
- usability engineering plans and user analysis,
- identification and classification of use errors,
- formative and summative testing with users,
- preparation of reports in accordance with IEC 62366-1 and ISO 14971.
We support SaMD, Class IIb/III, IVDs, and legacy devices transitioning to MDR compliance.
FAQ
Do usability tests need to be repeated if only the packaging or graphic design is modified?
Can usability studies be conducted remotely using digital simulations or VR?